On Stack Overflow, if a user casts a down vote, can there be a dialog or popup asking the reason for for the down vote? How can we know, whether the down-voter has judged properly? What are the parameters?

3 Answers
3

a pattern of downvotes from a single user will generally be reversed automatically

I put invalid in quotes because the design of the Stack sites is that users are allowed to vote up or down for whatever reason they want, and they don't have to justify or explain their votes. No-one can say your vote is wrong. While it might seem that this is crazy and leads to terrible voting, by and large it doesn't.

can there be a dialog or a popup asking the reason for down voting a post.

This already exists. When a user below 2000 rep downvotes a post, (s)he will get a popup asking for a comment. Of course, leaving a comment is still optional.

How can we know, if the down vote is judged properly ?

You don't. People can downvote for any reason they want including, (but not limited to):

Having a bad hair day.

Don't like you.

Revenge for some other (unrelated) episode.

And there's nothing you can do about it. That's just the way it works.

However, when a post has a lot of upvotes and a small number of (unexplained) downvotes, it's usually a clear indication that the downvotes are "misjudged" in some way. But in such cases, the upvotes offset the downvotes anyway. So it's not a problem.

What are the parameters ?

There are automated scripts to catch and reverse obvious voting abuse. And moderators have extra tools to detect voting rings and such. How these work are all secret for good reason.